Mex's teardown of a BCI Group 24 Lifeline AGM Battery
Mex sent the following write-up on the dissection he did of a dead Lifeline AGM battery. His internet connection has become very sporadic and non-existent at times so I would not expect him to be able to answer questions at this time, but please post your comments.
Bill
Why Lifeline Batteries Accept A Higher Amperage Charge
I shall do my best to simplify this yet not muddle mathematic principles. Several days ago I had an opportunity to dissect a non-functional BCI group 24 Lifeline AGM battery that had been stamped as manufactured May of 2001. I had to cut away the walls of the battery then separate the floor from the cells. The battery was then inverted and investigation was made with the battery upside down. Although I did not have my treasured loupe I managed to wrangle a pair of 5x diopter jeweler’s goggles then in addition use my 4” diameter magnifying glass in conjunction with the (safety) goggles to examine plates, separators and cell connectors.
Simple recitation of measurements found would be both boring and not very educational. Therefore construction techniques will instead be discussed.
· Ohms Law. The lower the resistance the greater potential exists for same-voltage higher amperage values. Function of current flow to resistance is a fundamental electrical principle.
· The Concorde Lifeline is advertised as having .105” cured positive plates which because of definite dimension battery jar capacity, must (?) limit the number of plates (and mats) per cell. Active plate surface area increases mean performance number (CCA and ampere hour) enhancement including maximum receptivity to charging voltage potential. Discussion of surface area / porosity permutations / performance shall be omitted here, being a moot complication.
· Absorbed glass mat batteries are based on a principle of acid starvation. Inherently a higher per (each) plate weight should mean fewer plates (thus less reactive area) furthering lower performance capacity. An excess of reactive plate surface area with resulting insufficient electrolyte means an inability to fully discharge and fully recharge the cell. The result would be a failed battery design.
· To compound the issue, plate alignment in a very crowded cell becomes much more difficult – consistent high alignment precision during production is mandatory. Single digit third decimal plate and mat alignment accuracy is absolutely called for (less than .010” error). This can only be achieved by laser controlled robotics or manual fanatically-labor-intense assembly discipline – the cost of the latter would disqualify the battery from being price competitive.
· But what about acid volume percentages? Excessive plate to electrolyte ratio would negate any “cell stuffing”
· Time for an analogy – Cut an exact square of terry-cloth measuring 12” x 12” and measure it’s weight dry. This would be the tare weight. Soak it in water, then reweigh it. This reveals the net weight of water contained.
· Measure the exact same dimensions of micro-fiber cloth, measure tare, soak it, and establish net weight.
· The micro-fiber cloth holds considerably more liquid yet occupies the same volume area. A huge difference in relieving the insufficient acid ratio syndrome in a crowded cell.
· Battery mat technology is considerably more complicated than that written above but a superior (read expensive) grade of mat allows for more acid retention per square millimeter, freer ion migration and thus a superior performing mat. A thinner mat is made possible.
· Up jumps the devil. Tolerances now become Lilliputian. Components therefore “squashed” together are a recipe for disaster. Dendrites could care less about superior matting. Without a barrier to prevent shorting dendrite bridging (mossing short) a tight tolerance AGM would be helpless against this problem. It is not uncommon for over-long dendrites to structurally “fail” due to unsupported mass versus vibration. But in a tight tolerance environment dendrite shorting would flourish and plate shorting events would be astronomically increased (even by reducing tolerances a mere .010”). Another fatal design flaw that must be avoided or cured.
· But if the plates were enveloped by an engineered porous membrane, dendrite structure could not penetrate this membrane. This process is called “Envelope Separators” and the Concorde Lifeline has them. So do many flooded batteries these days but in a squashed packed AGM battery how does a person “add” plate envelope separators?
· The fitting of envelope separated plates into an already tight construction again demands laser robotics, and ultra-strict assembly-line sampling to maintain quality control. The cell assembly mechanical precision is critical from start to finish.
· It is no secret that computer controlled laser robotic assembly machines cost millions of dollars each (and I must hazard a guess here and say a minimum of six assembly and six tolerance verification machines would be called for). As a strictly non technical aside: Contracts for military and aerospace battery production could underwrite a lot of high technology machinery. Concorde the manufacturer of Lifeline is a major defense industry contractor.
· But "tightly compactly cells" does not agree with the ultimate weight of the Lifeline versus other AGM brands. Again this demands an answer. Inter-cell lead busses were found during the examination to be considerably larger than those found in other AGM brands and busses occupy space. The same principle applies to end-cell-to-post connections – they were found to be larger in the Lifeline. Muse the point of passing a thousand amperes and the issue should come alive.
Therefore a basic form, the “characteristics uniqueness” of the Lifeline has “come to light.
Muse these above principles and extrapolate plate separator (mat) thicknesses and acid charge in relationship to charging and discharging characteristics of other types of absorbed glass mat batteries. Electrolyte is an electrical conductor but nowhere near as low resistance as lead. But what happens to electrical resistance when the space between lead plates is reduced or increased? What would you surmise the operational and charging characteristics of a thick mat, thick plate AGM battery to be in comparison to a Lifeline? Consider a thick mat, thick plate telecomm battery. Right about now, there should be a flash of your personal over-the-head light-bulb. But remember, few design specialties end up not being compromises in one form or another. Concorde Lifeline batteries are not inexpensive. And per pound of weight they render less at the 20 A/H rate than competitive brands. But when a group 31XT can be recharged from 50% DOD to 100% SOC in an hour and forty minutes the whole tally of pluses and minuses comes into play.
The Lifeline does have its quirks – rather than get needlessly mired into that drama, it is simpler to follow the Lifeline maintenance and charging manual instructions exactly.
A battery’s cost per kWh rendered should be a primary consideration. .105” plates versus .070” plates leaves .035” difference. Half again the thickness of a .070” plate.
Personal Opinion About The Concorde Lifeline Battery
As a BCI group the Lifeline offers fewer Cold Cranking Amperes than many competitive AGM batteries. Thus choosing a more expensive battery with weaker cranking power becomes questionable. The number of rigs that employ 1,000+ watt microwave ovens but see little long term off-grid camping usage would be another RV point in which higher cranking amperage lower cost AGM batteries may be a more cost-effective solution.
Roughly speaking comparing a Concorde Lifeline AGM battery to alternative brands would be similar to arguing positive and negative points of car-jar RV batteries versus GC-220 3-cell golf car batteries. Each type has its particular weak and strong points.
The strongest point of the Lifeline battery is the number of cycles it provides during its lifespan. It would not be considered unusual for a Lifeline to endure 150% of the number of cycles as compared to competitors. This must be mostly deduced from positive plate thickness comparisons and not from manufacturer’s advertising brochures. It is not coincidence that a decades-long flood of testimonials from cruising sailboat owners bears agreement with this statement.
-ENJOY-
Bill
Why Lifeline Batteries Accept A Higher Amperage Charge
I shall do my best to simplify this yet not muddle mathematic principles. Several days ago I had an opportunity to dissect a non-functional BCI group 24 Lifeline AGM battery that had been stamped as manufactured May of 2001. I had to cut away the walls of the battery then separate the floor from the cells. The battery was then inverted and investigation was made with the battery upside down. Although I did not have my treasured loupe I managed to wrangle a pair of 5x diopter jeweler’s goggles then in addition use my 4” diameter magnifying glass in conjunction with the (safety) goggles to examine plates, separators and cell connectors.
Simple recitation of measurements found would be both boring and not very educational. Therefore construction techniques will instead be discussed.
· Ohms Law. The lower the resistance the greater potential exists for same-voltage higher amperage values. Function of current flow to resistance is a fundamental electrical principle.
· The Concorde Lifeline is advertised as having .105” cured positive plates which because of definite dimension battery jar capacity, must (?) limit the number of plates (and mats) per cell. Active plate surface area increases mean performance number (CCA and ampere hour) enhancement including maximum receptivity to charging voltage potential. Discussion of surface area / porosity permutations / performance shall be omitted here, being a moot complication.
· Absorbed glass mat batteries are based on a principle of acid starvation. Inherently a higher per (each) plate weight should mean fewer plates (thus less reactive area) furthering lower performance capacity. An excess of reactive plate surface area with resulting insufficient electrolyte means an inability to fully discharge and fully recharge the cell. The result would be a failed battery design.
· To compound the issue, plate alignment in a very crowded cell becomes much more difficult – consistent high alignment precision during production is mandatory. Single digit third decimal plate and mat alignment accuracy is absolutely called for (less than .010” error). This can only be achieved by laser controlled robotics or manual fanatically-labor-intense assembly discipline – the cost of the latter would disqualify the battery from being price competitive.
· But what about acid volume percentages? Excessive plate to electrolyte ratio would negate any “cell stuffing”
· Time for an analogy – Cut an exact square of terry-cloth measuring 12” x 12” and measure it’s weight dry. This would be the tare weight. Soak it in water, then reweigh it. This reveals the net weight of water contained.
· Measure the exact same dimensions of micro-fiber cloth, measure tare, soak it, and establish net weight.
· The micro-fiber cloth holds considerably more liquid yet occupies the same volume area. A huge difference in relieving the insufficient acid ratio syndrome in a crowded cell.
· Battery mat technology is considerably more complicated than that written above but a superior (read expensive) grade of mat allows for more acid retention per square millimeter, freer ion migration and thus a superior performing mat. A thinner mat is made possible.
· Up jumps the devil. Tolerances now become Lilliputian. Components therefore “squashed” together are a recipe for disaster. Dendrites could care less about superior matting. Without a barrier to prevent shorting dendrite bridging (mossing short) a tight tolerance AGM would be helpless against this problem. It is not uncommon for over-long dendrites to structurally “fail” due to unsupported mass versus vibration. But in a tight tolerance environment dendrite shorting would flourish and plate shorting events would be astronomically increased (even by reducing tolerances a mere .010”). Another fatal design flaw that must be avoided or cured.
· But if the plates were enveloped by an engineered porous membrane, dendrite structure could not penetrate this membrane. This process is called “Envelope Separators” and the Concorde Lifeline has them. So do many flooded batteries these days but in a squashed packed AGM battery how does a person “add” plate envelope separators?
· The fitting of envelope separated plates into an already tight construction again demands laser robotics, and ultra-strict assembly-line sampling to maintain quality control. The cell assembly mechanical precision is critical from start to finish.
· It is no secret that computer controlled laser robotic assembly machines cost millions of dollars each (and I must hazard a guess here and say a minimum of six assembly and six tolerance verification machines would be called for). As a strictly non technical aside: Contracts for military and aerospace battery production could underwrite a lot of high technology machinery. Concorde the manufacturer of Lifeline is a major defense industry contractor.
· But "tightly compactly cells" does not agree with the ultimate weight of the Lifeline versus other AGM brands. Again this demands an answer. Inter-cell lead busses were found during the examination to be considerably larger than those found in other AGM brands and busses occupy space. The same principle applies to end-cell-to-post connections – they were found to be larger in the Lifeline. Muse the point of passing a thousand amperes and the issue should come alive.
Therefore a basic form, the “characteristics uniqueness” of the Lifeline has “come to light.
Muse these above principles and extrapolate plate separator (mat) thicknesses and acid charge in relationship to charging and discharging characteristics of other types of absorbed glass mat batteries. Electrolyte is an electrical conductor but nowhere near as low resistance as lead. But what happens to electrical resistance when the space between lead plates is reduced or increased? What would you surmise the operational and charging characteristics of a thick mat, thick plate AGM battery to be in comparison to a Lifeline? Consider a thick mat, thick plate telecomm battery. Right about now, there should be a flash of your personal over-the-head light-bulb. But remember, few design specialties end up not being compromises in one form or another. Concorde Lifeline batteries are not inexpensive. And per pound of weight they render less at the 20 A/H rate than competitive brands. But when a group 31XT can be recharged from 50% DOD to 100% SOC in an hour and forty minutes the whole tally of pluses and minuses comes into play.
The Lifeline does have its quirks – rather than get needlessly mired into that drama, it is simpler to follow the Lifeline maintenance and charging manual instructions exactly.
A battery’s cost per kWh rendered should be a primary consideration. .105” plates versus .070” plates leaves .035” difference. Half again the thickness of a .070” plate.
Personal Opinion About The Concorde Lifeline Battery
As a BCI group the Lifeline offers fewer Cold Cranking Amperes than many competitive AGM batteries. Thus choosing a more expensive battery with weaker cranking power becomes questionable. The number of rigs that employ 1,000+ watt microwave ovens but see little long term off-grid camping usage would be another RV point in which higher cranking amperage lower cost AGM batteries may be a more cost-effective solution.
Roughly speaking comparing a Concorde Lifeline AGM battery to alternative brands would be similar to arguing positive and negative points of car-jar RV batteries versus GC-220 3-cell golf car batteries. Each type has its particular weak and strong points.
The strongest point of the Lifeline battery is the number of cycles it provides during its lifespan. It would not be considered unusual for a Lifeline to endure 150% of the number of cycles as compared to competitors. This must be mostly deduced from positive plate thickness comparisons and not from manufacturer’s advertising brochures. It is not coincidence that a decades-long flood of testimonials from cruising sailboat owners bears agreement with this statement.
-ENJOY-
